Optical devices are commonly used in various environments to enhance the capabilities of the user's vision. In military environments, various optical devices are used to give a soldier enhanced visibility in limited conditions. For example, devices like the PVS 14 night vision monocular are commonly used in the military to enhance a soldier's visibility in low light conditions. These optical devices are affixed to combat helmets, weapons, or other structures that a soldier uses, and during a field operation, a soldier may move the optical device between the various mounting structures.
The use of a mounting shoe to secure an optical device to a mounting structure, such as a combat helmet or a weapon, is well-known in the art. FIGS. 1-3 are illustrations of an optical device mounting system, in accordance with the prior art. As is shown, the optical device 10 has a mounting shoe 20 secured thereto, such as with fastener 22. A pocket 30 is formed within the mounting shoe 20 (FIG. 1). The mounting shoe 20 engages with a receiver 40 of a mounting structure 50, as may be positioned on a combat helmet or weapon. A locking arm 60 protrudes into the receiver 40 such that when the mounting shoe 20 is engaged with the receiver 40, the locking arm 60 engages with the pocket 30 to securely retain the mounting shoe 20 within the receiver 40. To disengage the mounting shoe 20 from the receiver 40, the locking arm 60 may be withdrawn from engagement with the pocket 30, such as with buttons 70.
The optical device mounting system shown in FIGS. 1-3 is one type of mounting system—many others exist within the art. The shoe may have various designs, depending on the mounting structure the optical device is mounted to, and it is beneficial for the various designs of the shoe to be interchangeable with different mounts. Conventional shoes are commonly static, unitary structures with a dovetail shape and a plurality of angled sidewalls which allow the shoe to engage with a receiver. FIG. 4 is an image of a conventional mounting shoe 20, in accordance with the prior art. As is shown, the mounting shoe 20 has a dovetail shape with angled sidewalls, and a pocket 30 is formed in the center portion of the shoe 20.
While mounting shoes 20 are generally similar in size and shape, the receivers 40 in which they're engaged can vary in design. FIGS. 5A-5B are images of conventional receivers 40, in accordance with the prior art. Generally, receivers 40 are usually either utilize rear-engagement or forward-engagement to engage with mounting shoes 20, where the term ‘rear’ refers to the narrow end of the mounting shoe 20 and the term ‘forward’ refers to the wide end of the mounting shoe 20. For example, receiver 40A shown in FIG. 5A is a rear-engagement receiver, where the extended end 62 of the locking arm 60 makes contact with a raised tooth 32 along the edge of the pocket 30 at the rear side 24 of the mounting shoe 20. In contrast, FIG. 5B illustrates a forward-engagement receiver 40B, where the extended end 62 of the locking arm 60 makes contact with a forward edge 34 of the mounting shoe 20 along its forward side 26. As can be seen comparing FIGS. 5A-5B, the rear-engagement receiver 40A has a locking arm 60 which is positioned generally between the angled sides of the receiver 40A, whereas the locking arm 60 of the forward-engagement receiver 40B is positioned substantially in front of the space between the angled sides of the receiver 40B.
The use of forward or rear-engagement receivers may vary depending on the intended use of the mount. For example, the forward-engagement design is often used with receivers that use a locking arm or a butterfly clip commonly used to mount optical devices to weapons which may be exposed to heightened forces when the weapon is discharged. The rear-engagement design is often used with mounting optical devices to a combat helmet, which experiences less force. When a butterfly clip is used to engage a shoe along its forward edge, the mounting shoe may have an angled back surface, such as a 10° angle along the forward edge (at the wide end of the dovetail shape) to engage with a butterfly clip when the shoe is inserted into the mounting receiver. When a retractable locking arm is used with the receiver, as is shown in FIGS. 5A-5B, the shoe with the pocket is secured within the mounting receiver with a retractable locking mount which moves either into the pocket to engage with the shoe or along the forward edge of the shoe to engage with it.
While both types of shoe-engagements have been used for some time, manufacturing a shoe that is successful with both the forward-engagement and the rear-engagement has proved difficult. The shoe must be manufactured with extremely precise tolerances to allow the shoe to engage with the mounting receiver properly. Often times, a shoe with both types of engagement may fit with the forward-engagement but it will not fit with the rear-engagement, or vice versa. It is often difficult for manufactures to control the tolerances needed for the butterfly clip engagement, and failing to do so can prevent proper mounting of the optical device. For example, if the tolerance between the angled edge of the shoe and a forward-engagement locking arm or butterfly clip is too large, the shoe may be too loose within the mounting receiver, whereas if the tolerance is too small, the shoe may not lock within the mounting receiver at all, or the locking arm or butterfly clip may become jammed and not allow the shoe to be released.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.